{"id":"UBUNTU-CVE-2026-9539","details":"An out-of-bounds heap read and integer underflow in the TCP urgent data handling (sosendoob) in freedesktop.org libslirp version before v4.9.2 on hypervisor host environments (e.g., QEMU) allows a privileged guest VM attacker (root or CAP_NET_RAW) to leak gigabytes of sensitive host-process heap memory via sending crafted TCP segments with manipulated URG flags and urgent pointers (ti_urp).","modified":"2026-07-15T19:45:37.774769347Z","published":"2026-06-24T05:17:00Z","related":["USN-8550-1"],"upstream":["CVE-2026-9539"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-9539"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-9539"},{"type":"REPORT","url":"https://gitlab.freedesktop.org/slirp/libslirp/-/releases/v4.9.2"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8550-1"}],"affected":[{"package":{"name":"libslirp","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/libslirp?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.0.0-1","4.0.0-2","4.1.0-1","4.1.0-2","4.1.0-2ubuntu1","4.1.0-2ubuntu2","4.1.0-2ubuntu2.1","4.1.0-2ubuntu2.2"],"ecosystem_specific":{"binaries":[{"binary_version":"4.1.0-2ubuntu2.2","binary_name":"libslirp0"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-9539.json"}},{"package":{"name":"libslirp","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/libslirp?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.6.1-1ubuntu0.2"}]}],"versions":["4.4.0-1build1","4.6.1-1","4.6.1-1build1"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_version":"4.6.1-1ubuntu0.2","binary_name":"libslirp0"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-9539.json"}},{"package":{"name":"libslirp","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/libslirp?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.7.0-1ubuntu3.1"}]}],"versions":["4.7.0-1ubuntu1","4.7.0-1ubuntu2","4.7.0-1ubuntu3"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_name":"libslirp0","binary_version":"4.7.0-1ubuntu3.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-9539.json"}},{"package":{"name":"libslirp","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/libslirp?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.8.0-1ubuntu1"],"ecosystem_specific":{"binaries":[{"binary_name":"libslirp0","binary_version":"4.8.0-1ubuntu1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-9539.json"}},{"package":{"name":"libslirp","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/libslirp?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.9.1-1ubuntu1.1"}]}],"versions":["4.8.0-1ubuntu1","4.9.1-1ubuntu1"],"ecosystem_specific":{"binaries":[{"binary_name":"libslirp0","binary_version":"4.9.1-1ubuntu1.1"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-9539.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N"},{"type":"Ubuntu","score":"medium"}]}